4. Xiaohang is conducting a biochemical experiment for the next 12 months. In the first month, the expenses are estimated to be $15,000. As the experiment progresses, the expenses are expected to increase by 5 percent each month. Xiaohang plans to pay for the experiment with a government grant, which is received in six monthly installments, starting a month after the experiment completion date. Determine the amount of the monthly installment so that the total of the six installments pays for all expenses incurred during the experiment. Annual nominal interest is 12 percent, compounded monthly